Delineation of urban expansion and drought-prone areas using vegetation conditions and other geospatial indices

Drought is a dominant climatic feature in arid and semiarid regions. Climate change, temperature variability, and anthropogenic activities caused an increase in agricultural droughts in many regions. Investigation of drought dynamics is important for innovative planning and management of natural resources in drought-prone areas. Remote sensing indices and earth observational datasets were used in this study to investigate droughts in the Bikaner city of Rajasthan, India. Vegetation condition index (VCI), temperature condition index (TCI), and vegetation health index (VHI), estimated from multitemporal Landsat datasets, were used for monitoring the drought-prone areas. Land use land cover (LULC) map, normalized difference vegetation index (NDVI), and surface temperature were also calculated for monitoring the decadal changes in surface features. The results showed that barren lands decreased from around 162.75 to 79.59 km². The annual average temperature increased by 0.72 °C, while agricultural land increased by 33.83 km² during 1990‒2020. There was a gradual increase in droughts, but the increase was more in recent years than in the early period. The climatic condition revealed from VCI, TCI, and NDVI maps indicated most of the Bikaner city is prone to moderate and extreme droughts. The study indicates the need for VCI-based real-time drought monitoring for drought management.